1. Field
The technology of the present application relates generally to wireless devices having both positioning and transmitting capabilities, and more specifically to reducing interference between a wireless device's transmitter associated with the transmitting capabilities and receiver associated with the positioning capabilities.
2. Background
Mobile devices, such as, for example, laptop computers, handheld computers, cellular telephones, pagers, personal digital assistants, and the like are becoming ubiquitous. Mobile devices typically include a relatively high power transmitter that is used periodically to transmit information over a wireless network.
The addition of navigation or position locating systems to mobile devices is increasing as the technology for such position locating systems is becoming more cost effective, power efficient, and generally widely available. Position locating systems may use terrestrial signals, satellite signals, or a combination thereof. Many position locating systems, however, use satellites to facilitate determining the position of the wireless device. Satellite positioning systems (or SPS) include systems, such as, for example, the Global Positioning System (GPS—Originally titled NAVSTAR GPS when developed by the military) the Global Navigation Satellite Systems (GNSS), the Galileo positioning system (Europe), the Glonass (Russian), the Compass/Beidou (Chinese), the QZSS (Japanese), and the like. The position locating systems may be used for many applications including, for example, personal security, vehicle and personnel tracking, inventory control, and emergency response to name but a few applications of position locating systems.
Mobile devices using SPS generally include a highly sensitive SPS receiver to acquire and track the generally weak SPS signal. The highly sensitive SPS signal receiver can be affected by the co-located high power transmitter used to periodically transmit information from the mobile device. In one aspect, the high power transmitter couples and interferes with the SPS receiver. The interference may decrease the performance of the SPS receiver.
Some current approaches to overcoming the interference between the high power transmitter and the highly sensitive SPS receiver include the use of complicated filters or high dynamic range circuits in the SPS receiver to limit the interference. These approaches, however, may require the use of complex additional circuitry that can increase the cost and power consumption of the combined unit. For example, one method includes using band pass filters in the radio frequency front end of the SPS transmitter to reduce and possibly eliminate the radio frequency interference from the high power transmitter. Using band pass filters is problematic at best because often several filters are required increasing the number of parts, volume, costs and the like to add the additional parts to the mobile device. Moreover, using filters tends to increase the noise figure of the SPS receiver, making it less sensitive, which decreases performance.
Another approach to overcoming the interference between the high power transmitter and the highly sensitive SPS receiver includes turning the SPS receiver off while the high power transmitter is powered. This technique is generally known as “blanking.” While decreasing the complexity, size, and power drain of the aforementioned method, blanking also has drawbacks. One such drawback includes a decrease in the sensitivity of the SPS receiver due to the fact that it is turned off for a period of time. Turning off the SPS receiver hinders, for example, signal acquisition and tracking that may increase power consumption as the SPS receiver may take longer in its attempts to reacquire the signal.
Still another approach to overcoming the interference between the high power transmitter and the highly sensitive SPS receiver includes increasing the linearity of the SPS receiver, allowing it to function in the presence of the interfering signal. However, receivers that maintain linearity in the presence of strong signals, require more power to function. Increasing the power to the SPS receiver has drawbacks as well. Among other things, increasing the power needed by the SPS receiver consumes additional power reducing the available time of use from the battery.
Thus, improved apparatuses, methods, computer program products, and the like are needed to improve the operation of position locating systems in the presence of relatively high power transmitters.